The Present Disclosure relates generally to cable interconnection systems, and more particularly, to bypass cable interconnection systems for transmitting high speed signals at low losses.
Conventional cable interconnection systems are found in electronic devices such as routers and servers and the like, and are used to form a signal transmission line that extends between a primary chip member mounted on a printed circuit board of the device, such as an ASIC, and a connector mounted to the circuit board. The transmission line typically takes the form of a plurality of conductive traces that are etched, or otherwise formed on or as part of the printed circuit board. These traces extend between the chip member and a connector that provides a connection between one or more external plug connectors and the chip member. Circuit boards are usually formed from a material known as FR-4, which is inexpensive. However, FR-4 is known to promote losses in high speed signal transmission lines, and these losses make it undesirable to utilize FR-4 material for high speed applications (10 GHz and above). Custom materials for circuit boards are available that reduce such losses but the price of these materials severely increase the cost of the circuit board and, consequently, the electronic devices in which they are used. Additionally, when traces are used to form the signal transmission line, the overall length of the transmission line typically may well exceed 10 inches in length. These long lengths require that the signals traveling through the transmission line be amplified and repeated, thereby increasing the cost of the circuit board, and complicating the design inasmuch as additional board space is needed to accommodate these amplifiers and repeaters. In addition, the routing of the traces of such a transmission line in the FR-4 may require multiple turns and the transitions which occur at terminations affect the integrity of the signals transmitted thereby. It becomes difficult to route transmission line traces in a manner so as to achieve consistent impedance and a low signal loss therethrough.
The Present Disclosure is therefore directed to a high speed, bypass cable assembly that defines a transmission line for transmitting high speed signals, 10 GHz and greater that removes the transmission line from on the circuit board and which has low loss characteristics.